As illustrated in FIG. 12, a conventional ratchet wrench 50 comprises a rotating member 60, which can be rotated at the end of the wrench 50 and therefore to screw tight or loosen the nuts or bolts. The outer surface of the rotating member 60 is a ring gear structure 61, and the ring gear structure 61 intermeshes with the arc-shaped toothed surface of the ratchet member 70. The ratchet member 70 has on the other side an arc-shaped smooth surface 71 and can be operated within the space of the first chamber 51 of the wrench 50. The wrench has a second chamber 52 which is connected to the first chamber 51, and the second chamber 52 is installed with a control block 80. The control block 80 has an opening 81 at the end that faces the ratchet member 70, and a spring 82 is placed into the opening 81, with a spring cap 83 that covers the portion of the spring 82 that protrudes out from the opening 81. The spring cap 83, as being pushed by the compressed spring 82, pushes against the arc-shaped surface 71 of the ratchet member 70. By operating the control block 80 the places of the arc-shaped surface 71 to be pushed by the spring cap 83 may be selected, and the ratchet member 70 can thus be placed to the desired side of the first chamber 51, thereby allowing unidirectional rotational movement of the wrench 50.
The above-mentioned conventional ratchet wrench has the following structural deficiencies:
(a) As previously described, the spring 82 and the spring cap 83 are interposed between the ratchet member 70 and the control block 80, and the spring cap 83, as is pushed by the spring 82, pushes against the arc-shaped surface of the ratchet member 70. Therefore, when the wrench 50 is being rotated or when the control block 80 is being adjusted, the tip of the spring cap 83 pushes against and slides along the arc-shaped surface 71 of the ratchet member 70 and the other end of the spring cap 83 chafes laterally against the inner wall of the opening 81 of the control block 80, which may likely cause the spring 82 and the spring cap 83 to eject out from the opening or become deformed, and may also result in resistance force that reduces the operational stability of the conventional ratchet wrench. The conventional ratchet wrench thus is insufficient in structural strength and also may not allow smooth operation.
(b) The ratchet wrench 50 is installed following the procedures listed below: Firstly, the control block 80 is placed into the second chamber 52, and fixed by fastening steps to allow only the rotational movement of the control block 80. Secondly, the spring 82 is inserted into the opening 81 from the space of the first chamber 51, with the end of the spring 82 that protrudes out from the opening 81 enclosed into the spring cap 83. This installation step is rather difficult because the first chamber 51 opens towards the rotating member 60 and the space available for this installation step is limited and also because the spring 82 and the spring cap 83 are small in size they may get dropped or lost easily during the installation. Thirdly, it is necessary to place another spring 84 which also limits the positioning of the control block 80, and this additional step further increases the level of difficulty of the installation process, and likely causes excessive loss of components that are difficult to be manufactured.
(c) The spring 82 and the spring cap 83 is interposed between the ratchet member 70 and the control block 80, and the spring cap 83, as being pushed by the spring 82 within the spring cap 83, pushes against and slides along the arc-shaped surface 71 of the ratchet member 70. When ratchet member 70 is being moved, the spring cap 83 also pushes and compresses the spring 82, and this pushing maintains the space between the ratchet member 70 and the control block 80 for the movement of the ratchet member 70. During the movement of the ratchet member 70 within the first chamber 51, excessive portion of the spring cap 83 and the spring 82 may protrude out of the opening 81, which reduces the positioning effect on the spring 82 and the spring cap 83 therefore the spring 82 may eject out from the opening, get damaged, or get stuck. These deficiencies cause problems in practical uses thus further improvements are required.
The present invention provides a novel improved reversible ratchet wrench which solves the above-mentioned problems. The novel reversible ratchet wrench was developed as a result of the extensive research and is suitable for practical uses.